Refactor remote package to only have one remote cache impl.

Historically the remote package shipped two implementations
for remote caching: GrpcRemoteCache and SimpleBlobStoreActionCache.
Today there is no good reason to keep this structure and the
duplication of code and tests that comes with it. This is the
final refactoring of a long series:

 * 5fc91a7
 * 12ebb84
 * 8ac6bdc
 * 9fb83b4
 * 36611c3
 * a6b5b05
 * d40933d
 * 797f292

This change makes it so that there is one RemoteCache that
has a RemoteCacheClient. The RemoteCacheClient has one
implementation per caching protocol:

 * DiskCacheClient (formerly OnDiskBlobStore)
 * GrpcCacheClient (formerly GrpcRemoteCache)
 * HttpCacheClient (formerly HttpBlobStore)
 * CombinedDiskHttpCacheClient (formerly CombinedDiskHttpBlobStore)

A single RemoteCache type for all protocols will allow
composition of caching protocols. In particular, grpc and disk
caching. Additionally, this change will allow us to fix a longstanding
bug where for the HTTP

Closes #10200.

PiperOrigin-RevId: 279723411
diff --git a/src/main/java/com/google/devtools/build/lib/remote/RemoteActionInputFetcher.java b/src/main/java/com/google/devtools/build/lib/remote/RemoteActionInputFetcher.java
index 2d82bd6..72c6d54 100644
--- a/src/main/java/com/google/devtools/build/lib/remote/RemoteActionInputFetcher.java
+++ b/src/main/java/com/google/devtools/build/lib/remote/RemoteActionInputFetcher.java
@@ -65,11 +65,11 @@
   @GuardedBy("lock")
   final Map<Path, ListenableFuture<Void>> downloadsInProgress = new HashMap<>();
 
-  private final AbstractRemoteActionCache remoteCache;
+  private final RemoteCache remoteCache;
   private final Path execRoot;
   private final Context ctx;
 
-  RemoteActionInputFetcher(AbstractRemoteActionCache remoteCache, Path execRoot, Context ctx) {
+  RemoteActionInputFetcher(RemoteCache remoteCache, Path execRoot, Context ctx) {
     this.remoteCache = Preconditions.checkNotNull(remoteCache);
     this.execRoot = Preconditions.checkNotNull(execRoot);
     this.ctx = Preconditions.checkNotNull(ctx);